Fluid pressure actuated alarm device



Feb. 6, 1934. A. c. ROWLEY 1,946,412

FLUID PRESSURE ACTUATED ALARM DEVICE Filed April 13, 1933 Patented Feb. 6, 1934 UNITED STATES PATENT GFFICE FLUID PRE S S URE ACgUATED ALARM DEVIC Application April 13, 1933. Serial No. 666,042

3 Claims. (01. 200 83) This invention relates to improvements in alarm devices of a character adapted for use as an adjunct of fire extinguishing systems.

A principal object of the invention is to pro- 5 vide a novel alarm device adapted to operate by predetermined differences of fluid pressure developing in a fire extinguishing system of either the wet or dry pipe sprinkler type.

Another object of the invention is to provide an alarm device of the stated character which shall be simple in form and relatively inexpensive to manufacture and which shall be sensitive and durable and capable of efficient operation without attention over extended periods of time.

In the attached drawing:

Figure 1 is a longitudinal sectional View of a device made in accordance with my invention, and

Figure 2 is a view in perspective of the inner assembly of the device.

With reference to the drawing, a device made in accordance with my invention comprises a casing 1 of substantially cylindrical form and including at opposite ends detachable heads 2 and 3, respectively, which in the present instance are threaded into the ends of the body of the casing and each of which is provided with a port 4 and 5, respectively. These ports in the present instance extend through bosses 6, 6, which are externally threaded to provide means whereby the device may be assembled in the fire extinguishing system.

Adjacent each end of the cylindrical body of the casing 1 is a flange '7, '7 and between the outer face of each of these flanges and the associated head 2 or 3 of the casing is clamped the peripheral portion of a flexible diaphragm, these diaphragms being designated by the reference numerals 8 and 9. Intermediate each of the diaphragms and the adjoining casing head is a disk, 9 and 10 respectively, each having extending from one face th reof a stem 11, which stems, respectively, project into the ports 4 and 5. It will be noticed that the stems are of smaller diameter than the ports, leaving free passage through the latter. The concave inner face of each of the heads 2 and 3 is provided with a series of recesses 12 arranged around the ports 4 and 5 at a radial distance corresponding to radius of the disks 9 and 10, whereby when the disks lie against the head or in the position occupied in Fig. l by the disk 10, these recesses 12 cooperate with the concaved inner surfaces of the heads to maintain a continuous passage for fluid through the ports 4 and 5 to the interior chambers of the casing. In other words, these recesses 12 preclude the possibility of the disks 9 sealing the ports 4 and 5.

Mounted in the interior of the casing 1 between the diaphragms 8 and 9 is a cylindrical assembly shown in perspective in Fig. 2. This assembly comprises a central cylindrical core 13 which is solid in the present instance and of substantial Weight; and a plurality of open-ended cylinders 14, 15, 16 and 17, the said cylinders forming a concentric nest surrounding the core 13. The core 13 and the respective cylinders are freely slidable one with respect to the other in the axial direction.

As shown in Fig. 1, the core 13 carries intermediate its ends a transversely projecting rod 18, this rod being suitably fixed within the core and its opposite ends projecting through longitudinal slots formed in the cylinders 14, 15, 16 and 17 as illustrated. The extremities of the rod 18 are apertured for reception of threaded elements 19, 19, which are confined in the said apertures by nuts 20. Each of the elements 19 has a transversely extended head portion 21 and springs 22 are confined between the heads 21 and the adjoining sides of the rod 18, whereby the elements 19 are resiliently supported in the positions in which they are shown in Fig. 1, wherein the nuts 20 bear against the under sides of the end portions of the rod 18. As shown in Fig. 2, a pair of metallic strips 23, 23 are secured to the outer surface of the outer cylinder 1'7, these strips being so arranged that one end of each, respectively, overlies the elements 19, 19 and in these ends are mounted elements 24, 24, which are provided at their lower ends with transversely extended heads aligned with the heads 21 of the elements 19.

As shown in Fig. 1, the inner assembly 01' cylinders and associated elements is confined closely between diaphragms 8 and 9, the opposite ends of the assembly normally engaging the inner faces, respectively, of the diaphragm. Normally, and assuming an equalized pressure in the ports 4 and 5, the weight of the core 13 and of the associated elements is suiiicient to depress the diaphragm 9, the cylinders 14 to 17 inclusive conforming to the concave surface of the lower diaphragm as illustrated. In this relative position of the various elements it will be noted that the oppositely arranged elements 21 and 24 are separated from each other by an appreciable gap.

With reference to Fig. 2 it will be noted that the elements 23 and 24 constitute terminals of an electric circuit represented by the wires 25, 25,

which are respectively connected to said elements 23. It will further be apparent that when the elements 21 are elevated into contact with the elements 24, this circuit will be closed through 5 the medium of the connecting bar 18. Assuming therefore, with the elements in their respective positions shown in Fig. 1, the pressure in the port 4 drops to a substantial degree below that in the port 5, this unbalanced pressure on the diaphragms 8 and 9 will cause an elevation of the last-named diaphragm and a consequent elevation of the core member 13 bringing the switch elements 21 into contact with the elements 24 and thereby closing the electric circuit 25, which in practice will include a source of current and a suitable audible or visible electrically actuated alarm element. The upward movement of the elements 21 into contact with the elements 24 is less than the maximum possible movement of the core 13 by flexure oi the diaphragm 9, thereby insuring contact between the switch elements, while the springs 22 permit a relatively greater movement of the core 13 and the switch elements 21.

The sensitivity of this device and the amount at pressure required to close the alarm circuit may be readily determined by the weight of the core member 18 and of the associated concentric cylinders 14 to 17, inclusive. The cylinder 1'! and preferably also the cylinders 14, 15 and 16, are of insulating material such as hard rubber or hakeiite and the electric wires 25 are passed out from the casing 1 through a suitable opening not shown. It will be noted that due to the assembly of relatively movable concentric cylinders which embrace practically the entire eifective or exposed areas of the diaphragms, the fluid pressure applied to the one diaphragm is transmitted with substantial uniformity to the entire surface of the other diaphragm. The diaphragms thereby are not subjected to localized pressures and will give extended use with relatively slight wear.

It will be apparent that the device is subject to modification in the details of structure without departure from the invention.

I claim:

1. In a fluid-pressure-controlled electric switch device the combination with oppositely arranged diaphragm, of means for exposing the outer faces of said diaphragm to relatively variable pressures, and switch mechanism including a plurality of relatively movable telescoping elements confined between and embracing substantially the entire inner surfaces of said diaphragms and operatively associated with said diaphragm for movement therewith under the effects of relative variations in said pressures.

2. In a device of the character set forth, the combination with a casing, of a diaphragm secured within said casing and constituting the inner walls of independent chambers, said casing having ports communicating respectively with said chambers, a cylindrical member mounted between said diaphragms and movable with the latter, said member having transversely projecting arms, movable switch elements carried at the outer ends of said arms, a plurality of concentric cylindrical elements surrounding said first-named cylinder and movable with respect to the lastnamed cylinder and to each other, said cylindrical elements being operatively associated and movable with the diaphragms and having registering slots at opposite sides thereof for passage of the said transversely projecting arms, and relatively fixed switch elements secured to the outermost of said cylindrical elements in positions for operative association with the switch elements first named respectively whereby when said diaphragms are predeterminedly flexed by differential pressures in said chambers the switch elements are brought into contact with each other to close' an associated electric circuit.

3. In a device of the stated character, the combination with a pair of oppositely arranged spaced diaphragms, of means for subjecting the outer faces of said diaphragms to relatively variable fluid pressures, an assembly of concentric and relatively movable cylindrical elements confined between said diaphragms with their end surfaces in contact respectively with the inner faces of said diaphragms, said assembly embracing a substantial portion of the exposed faces of said diaphragms and being movable with the latter due to relative changes in the said fluid pressures, and electric switch mechanism operatively associated with said assembly and adapted to be predeterminedly actuated by relative changes in the said fluid pressures.

ARTHUR C. ROWLEY. 

